After meeting Trump, a fierce 2015 deal critic, French leader advocates for agreement that will build on current pact.

French President Emmanuel Macron has called for a new Iran nuclear deal that will build on the current agreement with Tehran, following talks with US President Donald Trump.

Macron, speaking on Tuesday at a White House press conference alongside Trump, said the pair held "frank discussions" on the landmark 2015 pact, which the United States president has previously described as "insane".

The agreement between world powers and Tehran, formally known as the Joint Comprehensive Plan of Action (JCPOA), eased sanctions on Iran in return for it agreeing that it would not develop nuclear weapons.

"We wish from now on to work on a new deal with Iran," Macron, who is on a three-day state visit to the US, said.

"Together, and with the powers of the region and Iranian leaders, we need to find a deal. This is the only way to bring about stability."

Any new deal must block all Iranian nuclear activity to 2025, prevent Iran from ever developing nuclear weapons, and contain Tehran's influence in countries throughout the Middle East, including Yemen, Syria, Iraq and Lebanon, Macron added.

Under the terms of the current agreement, Iran would be able to restart part of its nuclear programme from 2025 onwards as part of a so-called "sunset clause".

'Decayed foundations'

Trump, who has repeatedly criticised the JCPOA, faces a May 12 deadline to decide whether or not to renew sanctions relief for Iran.

On Tuesday, he said the existing deal has "decayed foundations" and warned Iran will face "big problems" if it resumes its suspended nuclear programme.

"France and the US agree that Iran cannot be allowed to develop a nuclear weapon and that the regime [in Tehran] must end its support of terrorism," Trump said.

"All over, no matter where you go in the Middle East, you see the finger prints of Iran behind problems."

Under US law, the president is required to renew the waiver on sanctions every 120 days. Trump last issued a waiver in January.

In October 2017, Trump refused to recertify that Iran was in compliance with the agreement. This put the fate of the deal in the hands of the US Congress, which had 60 days to decide whether to re-impose sanctions that would have likely killed the deal. The Congress, however, took no action.

Meanwhile, the International Atomic Energy Agency has repeatedly certified Iran's compliance with the deal.

Iranian reaction

Speaking earlier on Tuesday, Iranian President Hassan Rouhani called on Trump to uphold the deal, or "face severe consequences".

In a televised speech, Rouhani said the "Iranian government will react firmly" if the White House fails to "live up to their commitments" under the agreement.

Mohammad Javad Zarif, Iran's foreign minister, told AP news agency on Tuesday that an American withdrawal from the JCPOA would likely prompt Tehran to take similar action.

"If the United States were to withdraw from the nuclear deal, the immediate consequence in all likelihood would be that Iran would reciprocate and withdraw," Zarif said.